1. Field of the Invention
Embodiments of the present invention generally relate to a ring and ring assembly for an etching or other plasma processing chamber.
2. Description of the Related Art
In semiconductor processing chambers, substrates undergo various processes such as deposition, etching and annealing. During some of the processes, the substrate is placed onto a substrate support such as an electrostatic chuck (ESC), for processing. In an etch process a ring may be placed around the substrate to prevent erosion of the areas of the substrate support that are not covered by the substrate. The ring focuses the plasma and positions the substrate in place.
Rings are usually made of quartz material and are highly consumed in the etch process as they are exposed to etching gases and/or fluids. The rings are etched during wafer processing and need to be replaced after a set of substrates (wafers) are processed. The rings that are significantly eroded are usually replaced during wet clean. Wet cleaning is a process for removing etching residues using a cleaning chemical, and some of the cleaning chemicals may remain in the chamber after chamber cleaning. Therefore, the rings may be exposed to and eroded by the cleaning chemical. Thus, significantly reducing the service life of the ring. In some situations, a ring may need to be replaced after every wet clean, which leads to wastage of expensive quartz material.
Thus, there is a need in the art for a ring with an improved service life.